I have flies can't get rid of them.no food left out. No fruit. Really

treat your drains. that is where they lay eggs .

Fruit flies can be brought into the home with bananas, onions, etc. Try a dish covered in plastic and put a hole in the top so the flies can get in. The mix for the bowl is yeast, a little sugar, warm water, let rise. The smell of the yeast draws them in and they cannot get out. Another solution you could try is apple cider vinegar.

Check to make sure they are not coming from houseplants. Also check wherever you keep things like squash and potatoes. At my moms, I couldn't figure out where they were coming from until I checked the closet she keeps her onions, squash and potatoes. One of the potatoes in the bottom of the basket went bad on one end and it was swarming with the little buggers. Put up fly paper, they may be ugly, but they really do help. Pour boiling water down the drains in the kitchen, they are attracted to the moisture that stays in the drains and any residual food in the disposal. Take out your kitchen garbage really frequently until the are gone, as they will get in the garbage and breed. I hope this helps!

https://www.jcehrlich.com/flies/how-to-get-rid-of-flies/

i thought the she thing once n eventually found an old banana laying under something! That is the only way the flies will stick around- has to be fruit or something that you just haven't seen. My son's also used to throw food behind a cabinet that I never knew about till years later, lol, hate to admit it- but true. I knew when the one son told me that it was true- cause I knew that was something he would do. I wondered why they were so good about eating everything I fixed for them! Lol

Probably cluster flies.... https://www.domyown.com/how-to-get-rid-of-cluster-flies-a-227.html

Start with washing your fruits and veges because there are eggs on them. Then refrigerate them except the bananas. Since the eggs are now in the drain, you'll need to kill them with the baking soda/vinegar combo, when it stops fizzing, run hot water to flush it all out. Then cover your drain. For the flying ones, take 1/2 of a sticky cardboard (used for catching mice), peel off the protective layer and place a piece of decaying fruit in the center of it, The airborne ones will land and stay stuck, use the other half if needed.

Lavender, peppermint, eucalyptus, clove and basil herbs and essential oils can be effective in detering and preventing fruit flies: Place herbal tea bags around your kitchen. Add a few drops of essential oils to cotton balls and put them where you've seen fruit flies.

Put Rosemary Lavender and other strong smelling herbs in a vase of water, that don't like that!

Try this it might help catch them. https://www.hometalk.com/posts/outdoor/pest-repeller/homemade-fly-trap-21959026

Buy sticky traps - available on Amazon.